Hubby warned him once, already.
Since he is not my son, and he is a grown man, I am not sure about whether I should reveal that I went into his room and looked in his nightstand (which is actually my night stand).
It was hard to get him to like me when hubby and I first started dating, and we have a decent relationship, now, though tenuous. He is a difficult person, personality wise, so I try to stay out of any disciplinary issues.